However, the firm has been quick to put the blame on new legislation brought in by Ofgem and backed by the government which forces UK energy suppliers to limit the number of energy tariffs they can offer customers.

An E.on spokesperson said: "Due to new Ofgem rules, which includes limiting the number of tariffs we can offer, the StayWarm tariff will close as current contracts come to an end from October 7th."

Ofgem have hit back at the energy suppliers claims however, suggesting the firm could easily have continued with the StayWarm tariff if it had really wanted to.

An Ofgem spokesperson said: "We have never told suppliers which tariffs they have to close to comply with this rule, as that is a decision for them.

"In fact we have been clear with all suppliers that they would have been allowed to keep social tariffs (which for example offer discounts to customers who have difficulty paying bills) under our rules."

E.on still has another tariff for customers over 60 available, the Age UK one year fixed tariff. This provides protection for elderly energy consumers against price rises for 12 months.

E.on is part of the UK's 'Big Six' energy suppliers. It is part of the government's Green Deal initiative which allows energy consumers to contact their energy supplier about loans on products such as new boilers or wall insulation designed to improve a home's energy efficiency and cut down energy bills.